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<h1 class="title">edge.cpp 示例文件</h1>
<span class="subtitle">graphicsview/elasticnodes/edge.cpp</span>
<!-- $$$graphicsview/elasticnodes/edge.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  <span class="preprocessor">#include &quot;edge.h&quot;</span>
  <span class="preprocessor">#include &quot;node.h&quot;</span>

  <span class="preprocessor">#include &lt;qmath.h&gt;</span>
  <span class="preprocessor">#include &lt;QPainter&gt;</span>

  Edge<span class="operator">::</span>Edge(Node <span class="operator">*</span>sourceNode<span class="operator">,</span> Node <span class="operator">*</span>destNode)
      : arrowSize(<span class="number">10</span>)
  {
      setAcceptedMouseButtons(<span class="number">0</span>);
      source <span class="operator">=</span> sourceNode;
      dest <span class="operator">=</span> destNode;
      source<span class="operator">-</span><span class="operator">&gt;</span>addEdge(<span class="keyword">this</span>);
      dest<span class="operator">-</span><span class="operator">&gt;</span>addEdge(<span class="keyword">this</span>);
      adjust();
  }

  Node <span class="operator">*</span>Edge<span class="operator">::</span>sourceNode() <span class="keyword">const</span>
  {
      <span class="keyword">return</span> source;
  }

  Node <span class="operator">*</span>Edge<span class="operator">::</span>destNode() <span class="keyword">const</span>
  {
      <span class="keyword">return</span> dest;
  }

  <span class="type">void</span> Edge<span class="operator">::</span>adjust()
  {
      <span class="keyword">if</span> (<span class="operator">!</span>source <span class="operator">|</span><span class="operator">|</span> <span class="operator">!</span>dest)
          <span class="keyword">return</span>;

      <span class="type"><a href="../qtcore/qlinef.html">QLineF</a></span> line(mapFromItem(source<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>)<span class="operator">,</span> mapFromItem(dest<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>));
      <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> length <span class="operator">=</span> line<span class="operator">.</span>length();

      prepareGeometryChange();

      <span class="keyword">if</span> (length <span class="operator">&gt;</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">20.</span>)) {
          <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> edgeOffset((line<span class="operator">.</span>dx() <span class="operator">*</span> <span class="number">10</span>) <span class="operator">/</span> length<span class="operator">,</span> (line<span class="operator">.</span>dy() <span class="operator">*</span> <span class="number">10</span>) <span class="operator">/</span> length);
          sourcePoint <span class="operator">=</span> line<span class="operator">.</span>p1() <span class="operator">+</span> edgeOffset;
          destPoint <span class="operator">=</span> line<span class="operator">.</span>p2() <span class="operator">-</span> edgeOffset;
      } <span class="keyword">else</span> {
          sourcePoint <span class="operator">=</span> destPoint <span class="operator">=</span> line<span class="operator">.</span>p1();
      }
  }

  <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> Edge<span class="operator">::</span>boundingRect() <span class="keyword">const</span>
  {
      <span class="keyword">if</span> (<span class="operator">!</span>source <span class="operator">|</span><span class="operator">|</span> <span class="operator">!</span>dest)
          <span class="keyword">return</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span>();

      <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> penWidth <span class="operator">=</span> <span class="number">1</span>;
      <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> extra <span class="operator">=</span> (penWidth <span class="operator">+</span> arrowSize) <span class="operator">/</span> <span class="number">2.0</span>;

      <span class="keyword">return</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span>(sourcePoint<span class="operator">,</span> <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span>(destPoint<span class="operator">.</span>x() <span class="operator">-</span> sourcePoint<span class="operator">.</span>x()<span class="operator">,</span>
                                        destPoint<span class="operator">.</span>y() <span class="operator">-</span> sourcePoint<span class="operator">.</span>y()))
          <span class="operator">.</span>normalized()
          <span class="operator">.</span>adjusted(<span class="operator">-</span>extra<span class="operator">,</span> <span class="operator">-</span>extra<span class="operator">,</span> extra<span class="operator">,</span> extra);
  }

  <span class="type">void</span> Edge<span class="operator">::</span>paint(<span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span> <span class="operator">*</span>painter<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="qstyleoptiongraphicsitem.html">QStyleOptionGraphicsItem</a></span> <span class="operator">*</span><span class="operator">,</span> <span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>)
  {
      <span class="keyword">if</span> (<span class="operator">!</span>source <span class="operator">|</span><span class="operator">|</span> <span class="operator">!</span>dest)
          <span class="keyword">return</span>;

      <span class="type"><a href="../qtcore/qlinef.html">QLineF</a></span> line(sourcePoint<span class="operator">,</span> destPoint);
      <span class="keyword">if</span> (<a href="../qtcore/qtglobal.html#qFuzzyCompare">qFuzzyCompare</a>(line<span class="operator">.</span>length()<span class="operator">,</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">0.</span>)))
          <span class="keyword">return</span>;

      <span class="comment">// Draw the line itself</span>
      painter<span class="operator">-</span><span class="operator">&gt;</span>setPen(<span class="type"><a href="../qtgui/qpen.html">QPen</a></span>(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>black<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>SolidLine<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>RoundCap<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>RoundJoin));
      painter<span class="operator">-</span><span class="operator">&gt;</span>drawLine(line);

      <span class="comment">// Draw the arrows</span>
      <span class="type">double</span> angle <span class="operator">=</span> std<span class="operator">::</span>atan2(<span class="operator">-</span>line<span class="operator">.</span>dy()<span class="operator">,</span> line<span class="operator">.</span>dx());

      <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> sourceArrowP1 <span class="operator">=</span> sourcePoint <span class="operator">+</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span>(sin(angle <span class="operator">+</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize<span class="operator">,</span>
                                                    cos(angle <span class="operator">+</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize);
      <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> sourceArrowP2 <span class="operator">=</span> sourcePoint <span class="operator">+</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span>(sin(angle <span class="operator">+</span> M_PI <span class="operator">-</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize<span class="operator">,</span>
                                                    cos(angle <span class="operator">+</span> M_PI <span class="operator">-</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize);
      <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> destArrowP1 <span class="operator">=</span> destPoint <span class="operator">+</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span>(sin(angle <span class="operator">-</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize<span class="operator">,</span>
                                                cos(angle <span class="operator">-</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize);
      <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> destArrowP2 <span class="operator">=</span> destPoint <span class="operator">+</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span>(sin(angle <span class="operator">-</span> M_PI <span class="operator">+</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize<span class="operator">,</span>
                                                cos(angle <span class="operator">-</span> M_PI <span class="operator">+</span> M_PI <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize);

      painter<span class="operator">-</span><span class="operator">&gt;</span>setBrush(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>black);
      painter<span class="operator">-</span><span class="operator">&gt;</span>drawPolygon(<span class="type"><a href="../qtgui/qpolygonf.html">QPolygonF</a></span>() <span class="operator">&lt;</span><span class="operator">&lt;</span> line<span class="operator">.</span>p1() <span class="operator">&lt;</span><span class="operator">&lt;</span> sourceArrowP1 <span class="operator">&lt;</span><span class="operator">&lt;</span> sourceArrowP2);
      painter<span class="operator">-</span><span class="operator">&gt;</span>drawPolygon(<span class="type"><a href="../qtgui/qpolygonf.html">QPolygonF</a></span>() <span class="operator">&lt;</span><span class="operator">&lt;</span> line<span class="operator">.</span>p2() <span class="operator">&lt;</span><span class="operator">&lt;</span> destArrowP1 <span class="operator">&lt;</span><span class="operator">&lt;</span> destArrowP2);
  }

</pre>
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<!-- @@@graphicsview/elasticnodes/edge.cpp -->
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